A bisimide dicarboxylic acid made from a tricarboxylic acid anhydride and a diamine is industrially useful as a dicarboxylic acid raw material for polymers such as polyamide-imide and polyesterimide.
As a method for producing a bisimide dicarboxylic acid, there has been known a method in which a tricarboxylic acid anhydride and a diamine are reacted in a solvent (such as aliphatic carboxylic acids, N,N-dialkylcarboxylamides, alcohols, esters, and halogenated hydrocarbons). However, since the reaction is carried out in a solvent in the above method, it is necessary to separate and purify the bisimide dicarboxylic acid from the reaction solution after completion of the reaction in order to use the resulting bisimide dicarboxylic acid as a polymer raw material. Thus, it takes much time and energy.
Patent Document 1 discloses a method for mixing and reacting an aromatic tricarboxylic acid anhydride and a diamine. However, although the method of Patent Document 1 does not require separation and purification after completion of the reaction, mixing by an extruder, a kneader or the like is carried out, so that the resulting bisimide dicarboxylic acid is obtained in bulk. In order to use the bisimide dicarboxylic acid as a polymer raw material, the bisimide dicarboxylic acid should be granulated by pulverization, classification or the like. Thus, it takes much time and energy.